DAVID A. KESSLER has cred. As the commissioner of the Food and Drug Administration in the 1990s, he was a general in the war against Big Tobacco. On his watch, an FDA advisory panel declared nicotine addictive, infuriating the cigarette companies. He also tried to regulate cigarettes, though the Supreme Court eventually ruled that was an overreach. When Congress passed the Tobacco Control Act in 2009, finally giving the FDA authority over tobacco products, much of the legislation was borrowed from Kessler’s pathbreaking ideas.

Now a professor at the University of California at San Francisco, Kessler has stayed out of the fight between the pro- and anti-vaping camps, but he’s never stopped thinking about how to reduce the death and disease that result from smoking cigarettes.

The US is in the grip of a vaping crisis. When e-cigarettes first came on the market a decade or so ago, they were heralded as the thing that might end the scourge of cigarettes. It hasn’t worked out that way. True, many adult smokers have switched from cigarettes to e-cigarettes. But that good news has been overwhelmed by the very bad news that teenagers have enthusiastically embraced vaping.

More than a quarter of high school students are at least occasional vapers, government data show. Most of them use the sleek e-cigarette made by Juul Labs Inc., which packs a hefty nicotine wallop. Regular users risk becoming nicotine addicts. Parents are up in arms. Juul is facing accusations that it has marketed to kids (something the company denies). Whatever ideas the FDA might have once had about encouraging harm reduction via e-cigarettes, it is now singularly focused on getting them out of the hands of teenagers.

Which has brought Kessler into the conversation. A few weeks ago, I learned that he had spoken at a big conference about regulating tobacco. The conference wasn’t recorded, but Kessler, I heard, had proposed an interesting solution to the vaping crisis. I called him and asked him to spell it out for me. Here’s the bottom line: I think his idea is so smart — and so simple — that it really could succeed in keeping e-cigarettes out of the hands of youths while still making it easy for adult smokers to switch.

Kessler began by telling me that after the passage of the Tobacco Control Act, the FDA had hoped to use its new authority to mandate a gradual reduction in the level of nicotine in cigarettes, making them less appealing. At the same time, the agency hoped that new products would enter the market “that were scientifically established to be safer alternatives.” Indeed, in his early speeches, Scott Gottlieb, President Donald Trump’s first FDA commissioner, talked often about the promise of a reduced-harm strategy.

Then along came Juul Labs, which, in Kessler’s words, “came up with a product that ignited the youth market.” He added, “You cannot have the next generation become addicted before your eyes no matter how much you want to help the adult smoker.” Kessler cited one study that suggested for every smoker who switched to e-cigarettes, 81 teenagers would start vaping.

Kessler’s solution is what he calls “the Sudafed model.” The popular decongestant Sudafed contains pseudoephedrine, which can be used to manufacture methamphetamines. (See: Breaking Bad, season one.) To keep pseudoephedrine out of the hands of meth chemists, the federal government insists that any pill containing the drug be kept behind the pharmacy counter. But you don’t need a prescription to buy Sudafed; instead, you pick up a cardboard label on the drugstore shelf, hand it to the pharmacist, and affirm that you are buying it for yourself.

Kessler’s idea is to do the same thing with e-cigarettes. They would be withdrawn from other outlets, including liquor stores and gas stations, and sold only in drugstores, where users would find on the shelf the same kind of cardboard label, bearing the brand name of an e-cigarette. The pharmacist would then sell the product to customers who could prove they were over 21.

Given the many drugstores in the US, e-cigarettes would still be extremely accessible. But because pharmacists are generally more careful than gas-station clerks about who they sell to, it would become much more difficult for teenagers to get their hands on e-cigarettes.

I asked Kessler how he thought the companies were likely to react to his idea. “Right now, they’ll say no,” he replied. “The companies haven’t felt enough pain yet. They would still much rather have the clerk at the liquor store look at an ID like when they sell a six-pack of beer.”

But Kessler thinks we’ll reach the pain point soon enough. You see, by next May, every e-cigarette maker will have to submit their products to the FDA for approval. They’ll have to show that their products are appropriate “for the protection of the public health.” Kessler believes that no e-cigarette can qualify.

Partly, that’s because of the youth vaping epidemic. But it’s also far too early to know whether e-cigarettes are truly as safe as their proponents believe. Kessler told me he agrees with the growing consensus that the recent outbreak of lung disease is most likely related to vaping THC. Still, he said, “it’s humbling. It does show that as safe as you think the products are, you won’t really know for another 20 years.”

If he’s right, and the e-cigarette companies wake up one day and realize their products are likely to be rejected by the FDA, they’ll be willing to adopt the Sudafed model. At that point, it will be their only hope.

The government and the public health community, meanwhile, have focused from the start on keeping e-cigarettes away from kids. Assuming Kessler’s plan succeeds in doing that, then the public health world should have no problem making it possible for the 34 million adult smokers in the US to buy them.

I asked Kessler if he believed the FDA could do this on its own. He thought it could, but it would be better if the direction came from Congress. “Congress is engaged on this issue,” he said. “It’s in the best position to cut a deal with all sides.” A law would give the country faith that the Sudafed solution was not the work of some overzealous bureaucrat, but the will of the people.

There is one other benefit to the Sudafed solution. If it worked, it would finally put e-cigarettes in alignment with the goal of reducing or eliminating smoking. If that happens, David Kessler’s latest idea about tobacco will wind up being his best.